ADSORPTION OF DNA TO MICA, SILYLATED MICE, AND MINERALS - CHARACTERIZATION BY ATOMIC-FORCE MICROSCOPY

The nature of DNA adsorption to various substrates has been investigat ed by atomic force microscopy. The substrates used were mica, silylate d mica, calcite, fluorite, and barite. The presence of a divalent cati on, either in solution or accessible to the DNA on the substrate, grea tly improves DNA adsorption. A comparison of DNA adsorption from diffe rent buffers onto mica and silylated mica shows that buffer compositio n is much less important for DNA adsorption to silylated mica and also suggests that for good adsorption DNA must be electrostatically adsor bed to the surface.